1. Field of the Invention
This invention relates to an endoscopic apparatus using a covered type endoscope which is fitted in an endoscope cover by expanding the cover with an endoscope cover expander.
2. Description of the Related Art
Recently, uses of endoscopes have been increased in the field of medical treatment. During use of an endoscope in the field of medical treatment, it is possible that when the endoscope is inserted into a living body, body fluids will attach to an observation window provided in a fore end portion of an inserted section of the endoscope so that objects cannot be suitably observed through the window. To avoid this problem, an air supply tube and a water supply tube are provided to remove body fluids or the like attached to the observation window by blowing a fluid against the observation window by an operation at the operator side of the apparatus. In some cases, an aspiration tube for discharging unnecessary body fluids in an aspiration manner is provided.
There are endoscopes having a forceps channel (treatment instrument channel) which makes it possible to sample a tissue with biopsy forceps or to perform a treatment with a certain treatment instrument.
In the case of an endoscope provided with tubes and/or a forceps channel such as those mentioned above, washing and sterilizing operations are performed after use of the endoscope in a patient's body. However, the time required to achieve the desired effect of washing and sterilization is so long that the efficiency of use of the endoscope is considerably low, and sterilizing operations are troublesome.
In view of this problem, a covered type endoscope has been proposed which is used while being covered with an endoscope cover so that it can be maintained in a clean state during use, and which therefore require no washing and sterilizing operations.
For example, Japanese Patent Laid Open No. 3-29634 discloses a cover (sheath) for covering an inserted portion of an endoscope by being fitted around the inserted endoscope portion. To facilitate the operation of setting the inserted endoscope portion in the cover and the operation of detaching the endoscope portion from the cover, a cover portion for covering the inserted endoscope portion when the inserted endoscope portion is inserted into the cover is constructed so as to be able to expand by being supplied with air from a cover expander.
Fluid tubes are provided in the cover of the conventional covered type endoscope described above. During endoscopic examination, the fluid tubes of the cover and a universal cord of the covered type endoscope connect the endoscope in the cover and an external unit cart on which external units, such as a light source, air-supply and water-supply units, are mounted. The fluid tubes of the endoscope cover are connected to a fluid controller, and air and water are supplied and aspirated through the tubes through end portions formed at a fore end of the cover.
During examination handling of the endoscope, operations of twisting an operated endoscope portion connected to the inserted endoscope portion and inserting or extracting the operated portion are frequently performed. During such operations, a considerably large tensile force is applied to the fluid tubes of the endoscope cover and the universal cord of the covered endoscope. If the tensile force is larger than an allowable level, the fluid tubes of the endoscope cover or the universal cord of the covered endoscope is detached from the external unit. If the universal cord of the endoscope is detached, it may be reconnected. However, if the fluid tubes of the endoscope cover are detached, there is a risk of the fluid tubes and the external unit being contaminated. Thus, the conventional covered type endoscope has a drawback in terms of safety from infection.
To use the above-described conventional covered type endoscope for examination, an operation of attaching the covered type endoscope and the endoscope cover must be initially. It is necessary to perform this operation with the greatest of care so that the sterilized endoscope cover is not contaminated by being brought into contact with a floor and other things.
However, the endoscope cover is formed of an outer covering for the inserted portion of the covered endoscope and fluid tubes extending from the outer covering and is so long that it is difficult for an operator to perform the attachment operation by keeping the eyes upon the whole of the endoscope cover so that the sterilized endoscope cover is not contaminated, and there is a strong possibility of the endoscope cover being contaminated.
An aspiration tube may be used as a treatment instrument insertion path. Also, in the case of an operation of simultaneously using a plurality of treatment instruments, a covered type endoscope having a plurality of treatment instrument insertion paths and a plurality of aspiration tubes is used.
At the time of aspiration with a covered type endoscope having a plurality of treatment instrument insertion paths and a plurality of aspiration tubes, it is necessary to select the aspiration tubes according to examination situations. That is, the operator determines and sets the amount of aspiration according to various situations, including a situation where a large amount of a foul matter is to be aspirated, a situation where profuse bleeding is caused, a situation where it is desirable to perform soft aspiration without giving an impetus upon a mucous membrane, and a situation where a treatment instrument is inserted or not inserted in each aspiration tube.
However, an aspiration control valve of conventional endoscopic apparatuses using a disposable endoscope cover is provided in an external control unit, and the operator must operate it by reaching his or her hand to the external unit or operate it in a remote control manner with an expensive controller. In either case, a troublesome operation is required.